A Sundara (which is the same price) is more resolving, 100%. Now if you want to talk about comparisons to closed backs, things are more difficult. There is not a single closed back planar in this region that i know of (and the Maxwell has a very good sound isolation in comparison to other closed backs). The SJY Starry Night is more resolving (and very hard to drive), it's also a bit more expensive, but some models have dropped in price. I have not heard a lot of (closed back) dynamic drivers in that lower price region. It's been a while since i sold my Elegia, no idea how it would compare.
The Deva is most likely way worse than the Maxwell, Joshua Valour reviewed it a while ago and it wasn't impressive (bright, metallic timbre, loose bass, cheap build). The Ananda BT is there, probably more resolving, but i heard it has connection and build quality issues, of course it's also an open back. Focal Bathys is the thing that comes to mind, but it costs double, and i read that people prefer the sound of the Maxwell.
If you factor in the isolation and that it's wireless, with an extremely long battery life, there is no competitor when it comes to sound. I didn't even talk about the mic, because i don't use it at all.
P.s. Wiring the Maxwell does nothing for it since it uses it's build in stuff all the time, i actually got hickups and some issues when i plugged it into my RME ADI-2.